Data that has been secured in its digital form (e.g. encrypted, access restricted according to one or more permissions, or similarly protected) can still be surreptitiously accessed in its analog form. For example, a video that has been protected with various digital rights management (DRM) technologies can be recorded (for example, with a video camera) while being displayed on a screen. Similarly, the contents of a sensitive document on a screen could be viewed by an unauthorized party while it is being viewed by an authorized party (e.g. shoulder surfing).
These types of gaps are often referred to as the “analog hole.” If a sound can be heard by an ear, it can be recorded by a microphone. Likewise, if text, images, or video can be seen by the eye, they can be recorded by a camera. Historically, analog-to-digital conversion equipment has produced digital qualities of lower fidelity than the analog copy they are attempting to replicate. Further, this equipment tended to be bulky and therefore noticeable. These factors tended to limit the viability of exploiting the analog hole to gain access to secure information. However, cameras and other recording equipment have continued to decrease in size and increase in recording capabilities to the point where individuals can create high-quality copies of the analog presentation of secured data without being noticed. For example, a modern smartphone is often small enough to fit into the palm of someone's hand and includes both a high-resolution camera capable of capturing images with tens-of-millions of pixels and a high-fidelity microphone, allowing someone to photograph a display or record a conversation while standing next to the viewer or listener without being noticed.